Natural and Cultural History of North-East Australia's Wet Tropical Forests

Under provisions of the World Heritage Convention, in 1989, the United Nation's World Heritage Committee inscribed 900 000 hectares of north-east Australia's wet tropical forests on to the World Heritage list as being heritage of outstanding universal value to humankind.

This, then, is a history of this universally significant heritage. It is a natural and cultural history that reaches back to Gondwana, moves through time into the present, then onwards, 50 years hence, into a predicted globally warmer future.

This is a period of globally warm temperatures, and at latitudes higher (further towards the poles) than 45 degrees (from the equator) rainfall is high and there are extensive swamps (evidenced in the present by large coal deposits)[1]

What is presently called Australia, is, at this time, part of a single continent (Gondwana) comprised of an amalgamation of present Australia, Africa, South America, Madagascar, India, and Antarctica.[2]

At the location of present day northern New South Wales (Talbragar Fish Beds), there is a forested landscape dominated by Agathis (ie Kauri') together with podocarps (ie southern conifers), and in the understory are cycads, ferns, and tree ferns. Around the lake is a zone of seed ferns. Present day relict gymnosperm Agathis (Kauri) forests on the Atherton Tablelands represent a modern assemblage of plants with the same basic composition as the Jurassic (Gondwana) forests covering present day northern New South Wales (ie Podocarps [southern conifers] growing among the Kauri pines [Agathis robusta], with tree like cycads [Lepidozamia hopei] in the understory.[3]

West Gondwana (present Africa and South America) start to separate from East Gondwana (Australia, Antarctic, India, and Madagascar), with South America and Antarctic still connected for a while yet.[2] Various fragments of the northern margin of the present Australian plate also begin to detach and drift northwards to form an archipelago of terrestrial habitats (micro-continental fragments) between Gondwana and that other more northern continent, Laurasia [4]

This period (the Cretaceous) is a time of high global temperatures and high sea-levels, such that most of present Australia is covered by shallow seas, and the present land surface is divided into three major 'islands'.[1]

The remaining mass of what was Gondwana, still well south of present locations, allow warm oceanic currents to flow to high latitudes, with what would now be regarded as as tropical and sub-tropical climates southwards of 45 degrees down to 60 degrees south, and warm wet conditions reaching so far south that even the south polar regions have a relatively mild climate.[5]

The world's first evolutionary burst of angiosperms (see Glossary) occurs at this time.[6]. This evolutionary burst produced pollen of a type now (in the present) referred to by the fossil name Clavatipellonites. These Clavatipellonites appear and spread around the world (as it was then), though they don't yet reach Australia (part of East Gondwana).[6]

The world's first wind pollination dependent angiosperms appear in present tropical west Africa (now separated from East Gondwana) spreading poleward. The pollens of these plants are smaller, radially symmetrical grains, generally succeeding and replacing the Clavatipellonite pollens (and those plants communities that produced these pollens) around the world during this epoch., though, again (similar to the delay in the spread of the Clavatipellonites), they do not seem to reach Australia (part of East Gondwana) at this time.[6]

It is during this epoch that the world reaches its peak or highest global temperatures in over 500 million years (ie the highest temperature interval in the whole of the Phanerozoic Eon)[1]

It is first during this stage that the world's first angiosperms (represented in the fossil record by the Clavatipellonites) reach Australia and enter the Australian ecological mixes of the time, somewhat later than other parts of the world.[6][7]

Some of the northern fragments from the margin of the Australian plate, forming an archipelago between East Gondwana and Laurasia (present Burma and West Thailand) collide with the Laurasian Indo-China block (present east Thailand and Indo-China) [4]

There appears in Australia (and the associated Australian micro-fossil pollen record) plants might be considered ancestral, or somehow related to plants that now appear in present day Australian forests including Proteaceae, Ilex and Nothofagus [8]

From the beginning of this sub-era (the Tertiary), Australia's 'Great Dividing Range' has formed and stretches along almost the whole of the east coast of present Australia, constituting a highlands within a continent of otherwise relatively low relief. This range, in combination with the 'Great Escarpment' that suddenly drops off to the east for almost the entire length of the range, is a major landscape feature within Australia which will, for millions of years to come always experience relatively high rainfalls; will influence continental climatic patterns; and will effect future distributions and survivals of Gondwana descended flora and fauna.[9]

Also during this sub-era there are 'marine incursions' in present Southern Australia, flooding what is now the Nullabor Plain and the lower Murray Basin. [9]

Present Australia is still at high altitudes (much closer to the south pole than in the present), yet it remains relatively warm and wet, with rain-bearing clouds extending well inland (and, there is little or no ice in Antarctica).[10]

An abundance and diversity of cryptogams (ie ferns, mosses, algae & fungi: see Glossary) thrive in continuing moist conditions in Australia generally, and along the Great Dividing Range in particular.[11]. Gymnosperms still dominate the plant communities, but during this epoch there is also a significant increase in the prominence of Proteaceae (see Glossary) ancestors in particular.[12].

The sea-way between Australia and the Antarctica has begun to widen but it is still shallow, and there is therefore still relatively small differences in ocean temperatures from the equator to the high latitudes, with the climate over Australia still being warm and wet, though with a heavier winter rainy season in the south-east.[10]

The Australian continent is still covered, generally, with cool to warm, moist, closed forests, but the plant communities/assemblages themselves change noticeably from those of the previous epoch, with a dropping off in the earlier emergent prominence of the Proteaceae, and an associated emergence of an even greater diversity of angiosperm taxa[8] including tropical Olacaceae ancestors (now represented by a single species in present north-east Australia's wet tropical forests), ancestors (Cupanieae tribe)of the Sapindaceae, plus a salt water palm now known as Nypa (beginnings of present mangrove plant communities and eco-systems, presently represented in Australia by Nypa fruticans).[11]

The climate of the southern parts of Australia were almost tropical, the equivalent of which is now found in northern Australia, including, particularly, North-East Australia's wet tropical forests[13]:

i. at what is now Anglesea, Victoria (Australia), during this epoch, there was simple notophyll vine forest of a kind now found in north-east Australia's wet tropical forests (their closed analogue being the rainforest of Noah Creek, north of the Daintree River)

ii. what is now Golden Grove, South Australia, during this epoch, there was complex mesophyll vine forests of ancestor species that are presently represented within, and restricted to the complex mesophyll vine forests of north-east Australia's wet tropical forests.

Present Australian tectonic plate begins to move rapidly (on a geological timescale) northwards, separating from present Antarctica and separated by a shallow sea. At the same time the spreading between present India and Australia ceases, and the two separate plates 'coalesce' to form an Indo-Australian Plate.[4]

Circumpolar oceanic circulation developes during this Epoch, effectively reducing the transfer of heat from the equator southwards, which results in some cooling and lower rainfalls in the south of present Australian continent.[10]

As the present Australian continent drifts northwards, it passes over a fixed hot-spot in the underlying mantle, with Australia's oldest central volcanoes erupting in the north at this time, with later, younger central volcanoes erupting progressively southwards within the Australian continent.[14]

Present Australia's northward drift continues and, at this time, the Australian plate collides with the South-East Asian plate, ending 30 million years (ie 45 000 000 - 15 000 000) of isolation, and marking the first contact between Australia and South-East Asia.[4]

At the same time (15 million years ago) major change occurs in the Australian climate, with a pronouncing 'drying' accompanying the build up of the Antarctic ice-cap, and the associated southern hemisphere wind circulation starting to approach those of the present.[1]

At the beginning of this Epoch, the Australian continent is marked by it's aridity, which spreads northwards from the south as a belt of anticyclonic wind circulation develops (driven by the expansion of the Antarctic ice cap) closer migrates northwards from the higher latitudes.[1]

Human ancestors in this world (South Africa) are, by this date, using fire to cook shellfish (mussells); have started using ochres; and, for general anthropological purposes, these ancestors have skills, technologies, and lifestyles of a kind that is classed as 'modern human'[15],

By this Epoch, people (humans) were occupying, using, and living within the wet humid forests then prevalent in Melanesia.[16]. At this time, however, there were no large wet tropical forest in north-east Australia, and, instead, the 'rainforest' flora and fauna were largely preserved in riparian refuges, in a landscape that has been described as follows:

"The palaeoenvironmental evidence suggests that rainforest was unevenly distributed until 8300 BP, prior to which, much of the Atherton Tablelands was covered in sclerophyll woodland with patches of riparian rainforest in the deeper gullies"[17]

Quantities of charcoal particles within river sediments leap upward, together with noticeable changes in the kinds of pollens most prevalent in those sediments.

These charcoal particles and pollen fossils document and record a significant increase in the burning of the biomass of the river catchments out of which sediment has fallen. Together this record may signal the first arrival of Aboriginal 'burning' and Aboriginal 'fire regimes' into north-east Australia's ecological mix.[18]

James Mulligan ans party explore for gold and other minerals and, in the search, approach the western frings of the North-East Australia's wet tropical forests where they find a whole network of tracks linking Aboriginal camp sites (or 'townships' as Mulligan callsthem):

"A splendid track, the best native track I ever saw anywhere. There are roads off the main track to each of their townships, which consist of thatched gunyahs, big enough to hold five or six darkies. We counted eleven townships since we cam to the edge of the scrub, and we have only travelled four miles along it .. Their paths are well trodden, and we follow them sometimes for miles.."[21]

In the Queensland one 'settler' tells of the firm conviction amongst colonists that:

"their (Queensland Aboriginal peoples) stage of civilisation is too many hundreds and perhaps thousands of years behind our own to allow their race to thrive side by side with ours .. [and they] have learnt in their terrorto submit to anything that the conquering race may choose to do" [23]

Christie Palmerston discovers a number of patches of alluvial gold on the Rusell and Johnston Rivers, in the wet tropical forests between the tablelands and the coast, the 'slighest sign' of which brought a rush of European and Chinese prospectors.[25]

Swedish naturalist and anthropologist, Eric Mjöberg, collects flora and fauna (including mammals) from the tropical forests within the vicinity of a large Aboriginal camp (Djirbal)on Cedar Creek [dx]. He later writes:

"Most of the trees in the rainforest were giants, which had developed enormous buttress roots. The intelligent natives, who make use of their environment in every possible way, produce their large, beautifully painted shields from these roots. They also use the roots in a signalling system. By hitting the roots hard, they produce a shivering noise that travels a long distance through the rainforest."[27]

His Aboriginal companions pulled large pieces of bark from a rainforest evergreen flowering tree (Calophyllum [dx] species) to make water carrying bags (which the local Djirbal people called 'nobra')[dx][27].

Eric Mjöberg observed and later noted that by this time no stone artefacts are being used by these 'stone age' people, with the exception of grinding stones made from large flat basalt rocks (of which he collected examples). 'Grinding stones' were still being used to prepare nuts, fruits and roots for eating, and for grinding ochre during the wet season. During the dry season, he notes, the larger 'grinding stones' are left behind peoples huts or placed in tree branches to await people's return, and, instead, smaller 'hammer stones' or 'top stones' are used in the grinding process and are more readily carried around in lawyer cane baskets.[27]

Eric Mjöberg also specifically documented the extensive use Aboriginal [Djiribal] peoples at Cedar Creek [now Ravenshoe] were making of lawyer cane (Calamus Australis)

Eric Mjöberg, with Aboriginal companions as 'guides', explores southwards from Cedar Creek through the tropical forests collecting flora and fauna. His Aboriginal companions had advised him that when food was short around Cedar Creek, they'd walk their well beaten tracks through otherwise inaccessible forest, to fish for eel along the Tully River (dx). He later wrote:

"The rainforests we were travelling in were indeed thick and hard to get through. We stuck to the well-beaten native tracks they follow during their seasonal movements...On the third day we travelled through beautiful, dense, undisturbed rainforest. After a few hours we could see daylight filtering through the enormous trees and the roaring of a waterfall was getting louder. We had arrived at Tully Falls."[27]

Eric Mjöberg climbs to the cold peak of Mount Belleden Kerr [dx], later reporting that his Aboriginal companions, at that time, refused to climb to the top as it was the home of the great spirit 'Murgalainya' [dx].[27]

Queensland State Minister for Environment, Martin Tenni, supports Douglas Shire Council's efforts to bulldoze a road through from Cape Tribulation to Wujal Wujal[28]

"Martin Tenni .. suggested in an interview with the Courier Mail newspaper that drug racketeers had exchanged kidnapped girls for heroin on lonely Cape Tribulation .. The road, he believed, would put an end to this."

Angiosperms : of all the world's 'seed' plants, angiosperms are those plants whose 'ovules' (within which seeds are produced) are enclosed. Angiosperms are also known and referred to as the 'flowering plants' of the world.

Complex mesophyll vine forests: a forest type defined in large part by the range and kinds of leaves prevalent

Cryptogams : a convenient, though now taxonomically obsolete term used to refer to plants that reproduce by spores, or 'spore carrying plants' such as ferns, mosses, algae and fungus

Cycads : a gymosperm of a kind that was widespread during the Jurassic Period that with 'pinately compound leaves', sometimes confused with palms or ferns, the seeds for which contain a neurotoxin produced by blue-green algae.

Gondwana: southern super-continent that included most of the land masses of the southern hemisphere up until it started to detach and fragment during the Jurassic Period of the Mesozoic era.

Gymnosperms : of all the world's 'seed' plants, gymnosperms are those plants whose 'ovules' (within which seeds are produced) are not enclosed but are, rather, exposed on the edge of a leaf blade or within a cone like structure. The term 'Gymnosperm' comes a Greek word (gumnospermos) meaning 'naked seeds'.

Ilex : genus of angiosperms also known as Holly, with approximately 600 species around the world, ancestral species of which appearing in Australia during the Senonian stage of the Upper Cretaceous Epoch. Their small flowers are pollinated, primarily, by bees and/or insects and they bear small fruit.

Olacaceae: an angiosperm family of woody plants found presently found throughout the tropical parts of the world. Podocarpaceae: see Podocarps below

Podocarps : a gymnosperm consisting of large group of southern conifers or evergreens.

Proteaceae : family of angiosperms with approximately 80 genera, which occurs primarily in the southern hemisphere, including the Banksia and others with striking and distinctive flowers .. believed to be an angiosperm that finds its origins in the Gondwana super-contninent, now occurring on all those lands masses that were once part of Gondwana .. identifiable ancestor species for present day Proteacea appearing in Australia during the Senonian stage of the Upper Cretaceous Epoch.

Sapindaceae: angiosperm family also known as 'soap berries', which presently occur in temperate to tropical regions of the world and often have milky white sap. Lychees' rambutan, guarana are some of the more notable fruit bearing members of this family.

Simple notophyll vine forest: a forest type defined in large part by the range and kinds of leaves prevalent, a sample of which is the simple notphyll vine forest of Noah Creek, north of the Daintree River, North-East Queensland

Taxa : plural of taxon, being a taxonomic unit used to designate an organism or group of organisms - in a hierarchical naming scheme.

Atherton Tablelands : location of relict Agathis (Kauri) forests, being a present day, modern assemblage of plants with the same basic compostion as existed in the northern New South Wales of the Jurassic. Noah Creek : location of simple notophyll vine forest which is present day's closest analogue to the forests of this kind that existed during the Eocene epoch (greater than 38 000 000 years ago) at present day Anglesey, Victoria.

Nypa fruticans : palm descended from Nypa ancestral species in the Eocene, presently occurring South-East Asia and Northern Australia, being the only palm now considered to be a mangrove growing in salty mangrove conditions See